Kula onions are to Maui what coffee is to Kona.

The light-golden globes, grown on the western slopes of Haleakala at elevations of 1,200 to 4,000 feet, are a trademarked crop prized by celebrated chefs and home cooks alike for their mildness and sweet flavor.

At last weekend’s 22nd annual Maui Onion Festival at Whalers Village in Kaanapali, members of the Maui Onion Growers Association were quick to offer reasons for the onion’s highly desired characteristics.

"It’s the rich, volcanic soil," said farmer Bobby Ito, who was helping fry up tasty onion rings for sale at $5 a serving.

"It’s the indirect sunlight off the ocean," chimed in another farmer.

"It’s the cool nights and hot days," said Robin Shimabuku of the University of Hawaii’s Cooperative Extension Service.

Chris Speere, program coordinator for Maui Culinary Academy at University of Hawaii Maui College and a judge at the festival’s Best Maui Onion Recipe Contest, said the onion is such an integral ingredient that it’s often overlooked.

"On Maui we have fresh onions that have a sweet component to it that can carry many flavors," he said. "It’s key to a lot of cooking, and chefs now are being challenged to be cost-effective and are using braising, sous vide and other slow-cooking processes that draw out the flavors. Onions are important to that, and one of those foundational ingredients.

"And because Maui onions are local and fresh, the flavor is going to be that much better."

Kula onions, interchangeably labeled Maui onions, were the required ingredient at the festival’s cooking demonstrations by some of Hawaii’s top chefs, including restaurateurs D.K. Kodama and Roy Yamaguchi.

Yamaguchi said he "looks for the best-tasting onions in their raw state to judge how sweet they are."

The onions can be used in salads cooked or uncooked, sautéed and used as a bed, or puréed Italian style with olive oil and lemon zest, he said.

"With Maui onions you can’t go wrong," Yamaguchi said. "The sweetness will come out. Just season with salt and pepper."

Yamaguchi’s team entered a house-made Maui Onion and Molokai Shrimp Sausage in the recipe contest, but it was Kodama, working with Kaipo Nakata, executive chef of Kodama’s Cane & Taro restaurant at Whalers Village, who captured the title with his Maui Onion, Kekaha Shrimp and Lobster Cake with Swiss Chard, Hamakua Alii Mushrooms and Lobster Uni Sauce.